# DIY: Minimum Window Subsequence

Solve the interview question "Minimum Window Subsequence" in this lesson.

We'll cover the following

## Problem statement

Given strings ss and tt, find the minimum (contiguous) substring ww of ss, so that tt is a subsequence of ww.

If there is no window in ss that covers all characters in tt, return an empty string "". If there are multiple minimum-length windows, return the one with the left-most starting index.

### Input

The input will be two strings ss and tt. The following is an example input:

ss = "abcdebdde"
tt = "bde"


### Output

For the above input, the output will be:

"bcde"


The strings "bcde" and "bdde" are both minimum subsequences, but "bcde" occurs before "bdde".

## Coding exercise

For this coding exercise, you need to implement the min_window(ss, tt) function, where ss and tt are the provided strings. The function should return the minimum subsequence of tt that exists in ss.

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